Merging IconShape with ThemeManager

The order of initialization for IconShape is closely tied to ThemeManager
which makes it difficult for change listeners to work. Merging these keeps
all the theming information at one place

Bug: 381897614
Test: Updated tests
Flag: EXEMPT refactor
Change-Id: Ie29efa20c3308a24be3e284c1c93ed7444b68d58